No one wants to spoil Christmas dinner with a visit to the emergency room. But better the ER than the mortuary, right?

Multiple studies have shown that deaths spike during the holidays, but Christmas and New Year's days are particularly deadly. A 2004 study from the University of California-San Diego revealed that more people die from heart attacks on those two holidays than any other day of the year.

Talk about "Bah, humbug."

Doctors mostly lay blame for the deaths on patients' reluctance to seek help on the holidays. When the kids are opening presents Christmas morning or the gang's munching potato chips during the Rose Bowl on New Year's Day, it's easy to ignore symptoms of a heart attack or even write them off as indigestion, doctors say.

"We've definitely seen that people wait and ignore symptoms until the holidays are over. Only people who are really obviously sick come in over the holidays," said UCSF cardiologist Rita Redberg.

The death rate nationwide always climbs in the winter and over the holidays in particular. Violent deaths and suicides are more common this time of year, due in part to seasonal depression and stress, and people are more likely to die of the flu or other illnesses. So it stands to reason that more people would die on Christmas than on, say, the Fourth of July.

But even taking into consideration that more people die during the winter than any other time of year, there are roughly 5 percent more heart attack fatalities on Christmas and New Year's days than would be expected, according to the 2004 study, which analyzed 53 million deaths from 1973 to 2001.

"There are tens of thousands of extra deaths that are associated with the arrival of these holidays," said David Phillips, a sociology professor at UC-San Diego and an author of the study.

Doctors who have worked the holiday shifts say the statistics don't surprise them.

"Having worked 20 Christmases in a row, I can tell you, the death rate is much higher," said Eleanor Levin, a cardiologist with Kaiser Permanente in Santa Clara. She said the heart attacks she sees on the holidays are more likely to be fatal than the cases she sees the rest of the year, and there's no doubt it's due at least in part to delayed treatment.

It could be Mom not wanting to interrupt Christmas dinner or Grandpa refusing to go to the hospital before the last presents are unwrapped.

Also at play is probably the same factor that makes heart attacks deadlier on weekends than weekdays — there are simply fewer options for treatment, with many hospitals working with smaller staffs and some emergency rooms closing altogether.

It's also possible that at many hospitals, less-experienced employees are working the holidays as more senior doctors and nurses get the day off, Phillips said. Cardiologists also have wondered what role poor eating habits and extra stress have in holiday deaths.

Doctors and nurses who work around Christmas often refer to "holiday heart" — a condition that occurs when people who don't regularly drink alcohol tip back a few too many eggnogs and develop an irregular heartbeat. It isn't necessarily a dangerous condition, but it's frightening and can turn serious.

Redberg said she will often talk to patients about the risks of not taking care of themselves over the holidays. She reminds them about the importance of eating well and getting regular exercise, and advises them to stick to their usual routines as best they can.

The most important thing to keep in mind, doctors say, is to take seriously any heart attack symptoms rather than worrying about ruining Christmas.

Heart attack warning signs include chest pain, nausea

— You are experiencing chest pain or discomfort, which might feel like pressure, tightness or fullness in the center of the chest.

— You feel pain or discomfort in one or both arms, the back, neck or jaw, or the stomach.

— You have shortness of breath.

— You find yourself breaking out in a cold sweat.

— You are nauseated or vomiting.

— You feel light-headed.